Pneumatic tube.



No. s4s,|37. Patnwi Apr. 24, |900.

G. H. WODMAN.

PNEUMATIC TUBE.

(Application Bled May 21, 1898.)

(No Mudel.)

No. 641;,l37I Y A Patented Apr. 24, |900.

G. HLWUODMAN.

PNEUMATIG TUBE. (Applicatmn med may 21, 1898.) (No Model.) 2 Sheets-Sheet 2.

TRUE/014.

fairen STATES PATENT trice.

PN EU NIA-nc TUBE.

SPECIFICATION .forming part of Letters Patent No. 648,137, dated April 24, 1900.

Application filed May 2l, 1898. Serial No. 681,284. (No model.)

To all whom t may concern.'

Be it known that I, GEORGE H. WooDMAN,

of the city, county, and State of New York,

troduced into a tube when it is desired to ef-l fect the transmission ot' a carrier.

The invention embraces means for introducing and mechanically maintaining a flow of compressed air into a despatchtube, means operated by air pressure for automatically shutting ott' said dow of compressed air as soon after it has been so introduced as a sufcient volume of compressed air has been received into the tube to effect the transmission of a carrier through the tube, means for preventing any escape of compressed air into the atmosphere at the end of the tube where itis introduced, and, finally, means for diminishing noise at the farther open end thereof.

The method of operating pneumatic tubes by compressed air has decided advantages over the ordinary method of maintaining a constantly-Howing current of air through a tube-circuit by creating a partial vacuum therein. two stations. der automatic regulation. pressure is available. reliability are secured. Theheretofore-existing objections to 'the use of compressed air-namely, the lack ot' simple and reliable means for automatically governing the liberation ofjust therequisite Volumeof compressed airneeded for thein termittentdespatch of carriers and the disagreeable noise at both ends of the tubeare overcome by this invention. By the invention the desired results are attained solely by the operation ot' apparatus located at the stations from which the carrier is despatched and without the aid of any instrumentality requiring to be tripped into action by the carrier or of any connect-ions either electrical or mechanical between the opposite ends of the tube. f The mechanism for accomplishing these purposes consists, preferably, of a terminal structure, forming The supply plant can be un- Stronger force of .the terminal.

A single tube can be used betweenv Greater economy and the end of the despatch-tube, having an aperture in alinement with the tube for receiving carriers into the tube. This terminal has a connection with a compressed -airsupply pipe, a valve-chamber, a selfclosing valve, an intermediate chamber connecting the port of said valve with the despatch-tube, and a self-opening cover for closing the aperture of the terminal from the atmosphere. A manually-operative seltretracting valve controller or stem extending into the terminal and projecting outside the shell is adapted to close said cover by its initial movement when manually actuated, and by a further movement after the cover has become closed to unseat said self-closing valve. A stop acting automatically serves to hold the valve-controller in its extreme inward position, and hence to keep the cover closed and the self-closing valve open, thus admitting compressed air into the tube. The said valve-controller is automatically released to the infiuence of its retracting-spring by a releasing-piston seated in a piston-chamber connected to the terminal and having a passage for air-pressure comin unicating with the intermediate chamber 0f When the self-closing valve in the intermediate chamber is opened, the air-pressure passes immediately into the releasing-piston chamber, wherein it actuates the releasing-piston, which moves slowly as the oil contained in it is expelled through a leak-passage into the lower end of the releasepiston chamber. 'Ihe oil keeps the piston lubricated and insures a positive slow'movcment thereof. The length of its movement is adjustable in relation to the stop, and hence the duration otits movement can be limited to any period of time desired. It is accordingly regulated to make its movementin just the time consumed by a carrier in making a complete excursion through the tube. At the conclusion of its stroke the releasing-piston disengages said stop, and said valve-controller is thereupon returned to its normal position by its retractingspring. Simultaneously the compressed air in the chamber of the releasing-piston exhausts into the terminal and the releasing-piston returns to its starting-point by gravitation. While oil is preferred as a retarding agent, it is obvious that glycerin, mercury, and a variety of other IOO Vitself is the valve-controller.

The accompanying drawings, embodying the invention, are as follows:

Figure I is a longitudinal section of the end of the despatch-tube, the terminal, opening, cover, valve, valve-chamber, intermediate chamber, the releasing device, the valve-controller, and stop, showing the cover, valve, releasing device, and valve-controller in their respective normal positions when the tube is not in operation. Fig. II is a section taken through the plane indicated by the dotted line x a; in Fig. I. Fig. III is a side view of the outer end of the valve-controller and its supporting-sleeve, showing a modification in the organization by the addition of an arm and a lever and weight, adapting the valvecontroller to be retracted by gravity instead of by a spring. Fig. IV is a transverse sectional view of a modification of the terminal, showing the adaptation of the releasing device to operate an exposed latch and a cover, so organized as to perform the function of valve-controller. Fig. V is a transverse scctional View of another modification, wherein the valve-stem is adapted to be the valve-controller without any connection with the cover.

In the drawings, Figs. I, II, and III represent the end of a despatch-tube A, inserted in the chamber a, having the flaring mouth a. The cover B is adapted to slide in the recesses b and is connected by its pin b' with the slots h2 of the upright arms O, affixed to the hollow rock-shaft C, which is pivotally connected to lugs on the sides of the chamber D by its pin C2. The rock-shaft C has a short armrCS, adapted to be engaged by the inner end of the valve-controller F for the purpose of rocking the arms C into the position shown in dotted lines in Fig. I, and thereby forcing the cover B to its closed position, closing the mouth a'. The cover i's moved back to its open position when the force exerted upon the short arm C3 is released by the expanding spring C4, attached at one end to the wall ot' the chamber D and bearing at its other end against one of the arms C'.

The valve-chamber E is provided on its lowerouter wall with the pipe-union e for connecting it with a compressed-air-supply pipe. The valve E has its stem E2 projecting below it and above it. A guide for its lower end is furnished by the bridge e' and for its upper end by the bracket D'. It is held seated by its spiral spring E3 abutting at one end against the jam-nut under the valve and at the other end against the hub of the bridge e. The upper portion of the stem E2 has a slot provided with the 'roller E4 for bearing upon the under edge of the valve-controller F. Another roller D2, mounted upon the bracket D', bears upon the upper edge ofthe valve-controller F. The st'em fof the valvecontroller F projects through the tube F', which is inserted transversely across the releasing-piston chamber G and has its outwardly-projecting portion f enlarged in diameter, as shown, for the purpose of adapting it for receiving the tubular portion of the knob F2, which is screwed on the outer end ofthe valve-controller F, said tubular portion being of su fticient diameter to loosely contain a portion of the expanding spiral spring F3. The valve-controller has a transverse perforation f2, adapting it to receive and be locked by the pin or stop f3 when moved to its extreme inward position. When the valvecontroller is pushed inward, its first movement effects the closing of the cover B, as has been explained. By its further movement the cam f4 upon the under edge of the controller rides over the roller E, and thereby pushes down the valve-stein E2, nnseating the valve E' and admitting compressed air from the supply pipe into the chamber D and thence into the despatch-tube. In the meantime the locking-pin f3, by dropping into the perforation f2, locks the valve-controller in position. Immediately upon the introduction of compressed air into the chamber D it passes through the small passage d into the releasing-piston chamber G, between the two pistons 7L and h', affixed to the piston-stem h2. The lower piston h is provided with the passages hf", normally closed by the valve h, which by yielding in an upward direct-ion when the releasing-piston falls permits oil to iiow from the lower end of the chamber G r into the space between the two pistons 7L and h'. The lower piston h is also provided with a pas- IOO IIO

sage h5 of prescribed small cross-area, through which passage the oil from above lower piston 7L is slowly forced when the compressed airis admitted into the space between the two pistons. leasing-piston moves slowly upward.

The piston-stem h2 is slotted to allow the passage through it of the tube F'. The upper portion of the piston-stem h2 is vertically perforated to receive the locking-pin j? and is counterbored to enable it to contain the jamnuts f5 and f6, which are screwed on the locking-pin and by their position thereon determine the depth to which the locking-pin is permitted to descend into the perforation f2 in the valve-controller, and hence the duration of the period during which the valvecontroller is permitted to occupy its innermost position and hold the compressed-air valve open. When the releasing-piston has risen sufficiently to withdraw the locking-pin f3 from the Aperiz'oration f2, the valve-controller is released and is then retracted by its As the oil thus escapes the rc.

spring F2. The backward movement of the valve-controller is followed first by the closing of the compressed-air-supply valve E', and subsequently by the opening of the cover B after the pressure in the despatch-tube has subsided.

The compressedair, or, as it is colloquially designated, the pressure, in the releasingpiston chamber G, immediately upon the closing of the com pressed-air-supply valve E, exhausts into the chamber D, and thereupon the pistons h h drop by gravity.

During the upward movement of the pistons 7i h the air above the piston h' is permitted to escape through the opening in the cap G', through which the piston-stem h2 is loosely inserted. v

It will be seen that the compressed air is prevented from escaping from the space between the two pistons through the aperture f2 and the hollow upper portion of the pistonstem h2 by the cap 7L, screwed tightly upon the upper end of the piston-stem h2.

As the cover B is adapted to be completely closed before the com pressed-air-suppl y valve is opened and remains closed until after said valve is closed again (not being able to reopen after the valvecontroller releases it while there is pressure under it) there can be no escape of compressed air into the atmosphere from the terminal, and hence no noise. The sudden blast of pressure on opening said valve and its inrush into the tube would, however, make a disagreeable noise at the distant open end of the tube unless controlled. This control is accomplished by providing a multiplicity of passages D2 for the How of air between the chambers D and a, which by obstructing` the free passage of air between the intermediate chamber D and the despatchtube A raises the air-pressure available in the intermediate and piston chambers for operating the releasing-piston. A partition of finemesh wire-cloth is arranged across the path of the compressed air supplied from the chamber D to the despatch-tube. The despatchtube being smooth inside and several inches in diameter, freely transmits sounds, and in pneumatic tubes as heretofore constructed the inrush of compressed air at the sending end of the tube generates a roaring sound, which is carried through the tube and into the room where the carrier is to be delivered. The foraminous structure described breaks up the air-current and almost entirely prevents the generation of such sound.

In the modification illustrated in Fig. IV the chamber ct communicates on one side with the air-supply-valve chamberE through passages I and on the opposite side is provided with a lateral extension J. The expanding spring F3 on the stem f tends to hold the cover l in the extension J. l/Vhen a carrier is to be despatched, it is deposited in the tube A and the cover B is pushed inward by manually-exerted pressure upon the knob F2. In

its inward movement the cover B, after having closed the mouth o,encounters and pushes backward the stem E2 of the air-supply valve E, thereby opening the valve E and admitting pressure from the valve-chamber E into the chamber d behind the carrier. During the concluding portion of the inward excursion of the cover B the under edge ofthe knob F2 rides over and is caught by the latch t', pivoted to a bracket on the under side of the extension J. It will be perceived that the latch t' is the equivalent of the stop-pin f3, hereinbefore described. In this modification the releasing device is arranged beneath the extension J and is operated by compressedl air supplied through the narrow passage j from the chamber a. The releasing deviceis composed of the solid stem K, having affixed to it the hereinbefore-described pistons hand 71"', seated in the piston-chamber K'. At its upper end the stem K is provided witha vertically-adjustable screw K2. Then the releasing device is operated, the head K3 of the screw K2 bears against and lifts the longer arm t" of the latch t', and thereby disengages the latch t' from the knob F2 and releases the cover B to the retracting action of its spring F2. screw K2 serves to vary the duration of the period during which the cover B remains in its closing position and'keeps the air-supply valve E' open.

In the modification illustrated in Fig. V the cover B is hinged, and in its open position hangs vertically downward in the chamber a, out of the path of travel of the carrier and across the opening of the chamber D. This position adapts it to be blown into its closing position by the compressed air introduced into the chamber D. Until relieved from said air-pressure the cover B is held against the oblique under end of the flaring mouth d', thus shutting off the despatch-tube A from communication with the atmosphere through said flaring mouth. The air-pressure is introduced into the chamber D through the valve E of the valve-chamber E, which is connected with the compressed-air-supply pipe e. The stem E2 of the air-pressure valve E is elongated suiiiciently to extend vertically through the chamber D and through the cap at the top ofthe terminal. At its upper end the stem E2 is provided with the knob F2, which has a downwardly-projecting hook adapted to catch under the latch t', suitably pivoted to lugs on the cap of the terminal. The arm t" of the latch t' extends laterally outward in position to be engaged and lifted bythe head K3 of the adj Listing-screw K2, inserted in the stem K of the releasing-piston, which in construction and mode of operation is similar to the releasing device shown in Fig. IV. W'hen the valve-stem E2 is moved downward by manually-exerted pressure upon the knob F2, the valve E is unseated andis held open so long as the knob-F2 remains in engagement with the latch i. The force of the compressed air introduced into the chamber D closes the Varying the adjustment of the' IIO cover B and the compressed air continues to flow from the supply-pipe through the chamber D into the despatch-tube A until the releasing-piston trips the latchiin the manner previously described. It will be noticed in this modification that the elongated valvestem E2, which serves as the valve-con troller, is rendered self-retracting by the spring of the self-closing valve E', which makes unnecessary a special spring forthe purpose, as is provided in the construction shown in Fig. I.

The modifications hereinbefore described furnish illustrations of some of the various forms of mechanical construction in which these improvements may be usefully applied without departing from the broad invention.

Another important advantage afforded by the invention is that a second carrier or a numberof carriers in succession can be transmitted through the despatch-tube without waiting for a carrier previously started to complete its journey.

By the present invention, as illustrated in Figs. IV and V, the valve-controller may be manually released to secure the opening of the cover for starting another carrier at any time while the tube is in operation, and immediately the releasing-piston will drop to its normal position. Upon the valve-controller being again operated the releasing piston will make its 4full movement, releasing the valve-controller, and thereby shutting off the air-pressure after the carrier last started has been expelled from the tube.

What is claimed as the invention isl. Apneumatic-despatch tube; connections `for supplying compressed air thereto; a selfclosing valve for controlling the supply of compressed air; a stop for holding said valve open; a releasing device including a pressureactuated piston for releasing said stop; and a liquid-escapement device for compelling a predetermined slow operative movement of said piston, during the fiight of the carrier.

2. Apneumatic-despatch tube, connections for supplying compressed air thereto, a self-V closing valve for controlling the supply of compressed air, a stop for holding said valve open, a releasing device including a pressureactuated piston for releasing said stop, a liquid-escapement device for compelling a predetermined slow operative movement ot' said piston, and means to provide for a quick return movement of said piston.

Apneumatic-despatchtube,connections for supplying compressed air thereto, a selfclosing valve for controlling the supply of compressed air, a stop for holding said valve open, a releasing device for said stop operative by the compressed air upon opening said valve and a liquid-escapement device for controlling the movement of said releasing device and to determine the time for releasing the stop.

1t. A despatch-tube: a supply-pipe for supplying compressed air thereto: a self-closing valve for controlling the compressed-air supply: a self-retracting valve controller for opening said valve by its movement in one direction: a stop for holding said valve-controller stationary at the end of its said movement: means for automatically releasing said valve-controller from said stop: a self-opening cover for said despatch-tube: means for closing said cover and for opening said airsupply valve at different prescribed stages in the operative movement of said valve-controller: and means for releasing said air-supply valve and said cover at different prescribed stages in the retracting movement of said valve-controller.

5. A pneumatic-despatch tube; a conduit for supplying compressed air thereto; a valve for admitting compressed air to said conduit; and a finely-perforated screen arranged across the path of travel of the compressed air between said valve and said despatch-tube, for the purpose of creating increased air-pressure in the valve-chamber and preventing the loud sound ordinarily generated by the inrush of the compressed air into the sending end of the despatch-tube.

6. A pneumaticdespatch tube; connections for supplying compressed air thereto; a self-closing valve for controlling the supply of compressed air; a stop for holding said valve open; a piston for throwing said stop out of action; and means for varying the range of the operative stroke of said piston.

7. A pneumatic despatch tube; connections for supplying compressed air thereto; a self-closing valve for controlling the supply of compressed air; a stop for holding said valve open; a releasing device for releasing said stop embracing a pressure-operated piston; a chamber for containing a liquid; connections for supplying compressed air to said chamber While said valve is open; a restricted passage affording an escapement for said liquid in one direction under the pressure of compressed air introduced into said chamber, for the purpose of compelling a predetermined slow operative stroke of said piston; and a passage of relatively -larger area provided with a check-valve adapted to yield and permit a copious flow of liquid in the opposite direction for insuring a rapid return stroke of said piston.

GEO. Il. WOODMAN. Witnesses:

C. M. POWER, R. K. GoonLIFFE.

IIO 

